Thankful Eyes is a bookmarklet which automatically calculates and applies a large enough font size to body text for optimum readability. It’s a little project I worked on recently, and I think it is ready for general beta testing and real-world usage. It works in Opera and Firefox (untested in IE). Known not to work under Safari or Chrome [yet].

It is said that, for optimum readability, text line length should be around 12 words per line. This allows the eye to easily track from the end of one line to the beginning of the next.

Using Thankful Eyes is better than simply maintaining a minimum font size with your browser settings because doing that increases the size of many elements which usually do not require magnification, such as sidebar text, menu items, small labels, and so on. Thankful Eyes aims to adjust only body text. It’s also better than using browser zoom, because browser zoom also magnifies and distorts images.